The r/R-band absolute-magnitude light curves of a few type-Ic SNe from the literature, compared to that of iPTF15dtg, which is declining much more slowly. The references for these light curves are listed in Fig. 3 of T16. Supernova 2010mb data are from Ben-Ami et al. (2014). The late-time ⁵⁶Ni + ⁵⁶Co luminosity expected from the amount of ⁵⁶Ni estimated from the peak of iPTF15dtg is marked by a dashed black line.